/*
 * Copyright � 2002-2011 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using System.Reflection;

namespace Spring.Aop.Support;

/// <summary>
/// A <see cref="Spring.Aop.IPointcut"/> union.
/// </summary>
/// <remarks>
/// <p>
/// Such pointcut unions are tricky, because one cannot simply <c>OR</c>
/// the respective <see cref="Spring.Aop.IMethodMatcher"/>s: one has to
/// ascertain that each <see cref="Spring.Aop.IMethodMatcher"/>'s
/// <see cref="Spring.Aop.IPointcut.TypeFilter"/> is also satisfied.
/// </p>
/// </remarks>
/// <author>Rod Johnson</author>
/// <author>Aleksandar Seovic (.NET)</author>
[Serializable]
internal class UnionPointcut : IPointcut
{
    private IPointcut a;
    private IPointcut b;
    private IMethodMatcher mm;

    /// <summary>
    /// Creates a new instance of the
    /// <see cref="Spring.Aop.Support.UnionPointcut"/> class.
    /// </summary>
    /// <param name="firstPointcut">The first pointcut.</param>
    /// <param name="secondPointcut">The second pointcut.</param>
    public UnionPointcut(IPointcut firstPointcut, IPointcut secondPointcut)
    {
        this.a = firstPointcut;
        this.b = secondPointcut;
        this.mm = new PointcutUnionMethodMatcher(this);
    }

    /// <summary>
    /// The <see cref="Spring.Aop.ITypeFilter"/> for this pointcut.
    /// </summary>
    /// <value>
    /// The current <see cref="Spring.Aop.ITypeFilter"/>.
    /// </value>
    public ITypeFilter TypeFilter
    {
        get { return TypeFilters.Union(a.TypeFilter, b.TypeFilter); }
    }

    /// <summary>
    /// The <see cref="Spring.Aop.IMethodMatcher"/> for this pointcut.
    /// </summary>
    /// <value>
    /// The current <see cref="Spring.Aop.IMethodMatcher"/>.
    /// </value>
    public IMethodMatcher MethodMatcher
    {
        get { return mm; }
    }

    /// <summary>
    /// Internal method matcher class for union pointcut.
    /// </summary>
    [Serializable]
    private sealed class PointcutUnionMethodMatcher : IMethodMatcher
    {
        private UnionPointcut _enclosingInstance;

        public PointcutUnionMethodMatcher(UnionPointcut enclosingInstance)
        {
            this._enclosingInstance = enclosingInstance;
        }

        public bool IsRuntime
        {
            get
            {
                return _enclosingInstance.a.MethodMatcher.IsRuntime
                       || _enclosingInstance.b.MethodMatcher.IsRuntime;
            }
        }

        public bool Matches(MethodInfo method, Type targetType)
        {
            return (_enclosingInstance.a.TypeFilter.Matches(targetType)
                    && _enclosingInstance.a.MethodMatcher.Matches(method, targetType))
                   || (_enclosingInstance.b.TypeFilter.Matches(targetType)
                       && _enclosingInstance.b.MethodMatcher.Matches(method, targetType));
        }

        public bool Matches(MethodInfo method, Type targetType, object[] args)
        {
            // 2-arg matcher will already have run, so we don't need to do type filtering again...
            return _enclosingInstance.a.MethodMatcher.Matches(method, targetType, args)
                   || _enclosingInstance.b.MethodMatcher.Matches(method, targetType, args);
        }
    }
}
